Storm and surge alarm for transmission-lines.



E. E. F. GREIGHTON= STORH AND SURGE A LABM FOB. TRANSMiSSIGN LIKES. APPLICATION FILED snrr. 2, 1903.

1,062,083, Patent-ed may 20, 1913.

Witnesses: Inventor:

1 Elmer ELF Crei hton,

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Specification Letters Patent.

Patented May 20,1913.

To all whom it may concern:

Be itknown that I, Emma E. F. Camourox, a citizen of the United States, residing at Schenectad county of Schenectady,

6 State of New ork, have invented;certa1n new and useful Improvements in Storm and Surge Alarms for Transmission-Lines, of which the following is a specification.

This invention relates to devices for rotecting high tension transmission lines rom the injurious effects of surges of abnormal potential, due either to lightning, short circuits, improper handlin of switches, or to other causes. In case 0 a disturbance from any reason, it is desirable that an attendant be notified, even though the trouble may not have reached a value that will operate the lightning arresters. If the disturbance is known to exist, a search can be made to locate the defective circuit and disconnect it whenever desirable. In this way a eneral interruption of service can be avoide For instance, when a thunder storm approaches a transmission line, the disturbance on the line becomes more and more severe as the storm draws nearer. If an alarm notifies the attendant that somewhere out on the line a storm is approaching he will be more actively ready to operate his switches and observe the action of the lightning arresters.

The present invention consists of an apparatus responsive to surges of high tension and operating an alarm at the station to give warning of dangerous conditions along the line. It comprises a small wire running parallel with the line and having one end grounded through a coherer which controls a local circuit containing an alarm, and, if desired, a relay for operating an electromagnetic switch in the lightning arrester circuit.

In the accompanying drawing, Figure 1 is a View partly in erspective and partly in diagram, illustrating an embodiment of my invention; Fig. 2 shows a control circuit which may be connected with the apparatus shown in Fig. 1; Fig. 3 shows the relative position of the line conductors and the alarm wire; Fig. 4 is a similar diagram showing four alarm wires; and Fig. 5 shows a modified alarm system.

The transmission line illustrated is a three-phase line, havingthe three conductors shown, located in the center of the triangle formed by the line conductors so as to be equidistant from all of them. The'alarm wlre runs for any desired distance and terminates at one end in mid air. The other end is led down to ground at 5, through a condenser 6 and a co erer 7, and is also permanently grounded through a high resistance path consisting of a non-inductive shunt 8 of high resistance, placed around the condenser, and a shunt 9 containing inductance and resistance and connected around the coherer. B means of this high resist ance shunt pat the accumulation on the alarm wire of unidirectional static charges due to wind'and similar causes, is prevented. If such charges were not removed they would accumu ate and strain the condenser 6, and might cause sparks which would af-- feet the coherer and cause false indications.

In another circuit in shunt to the coherer is I a battery 10 and an electric alarm, such as the bell 11.' If desired, a relay magnet 12 may be included in this circuit, to open and close a circuit 13' which may contain any suitable control apparatus, such as an electromagnetic switch in circuit with a gap aluminum lightning arrester, as shown in Fig 2.

he operation is as follows: Under ordinary conditions the inductance on the alarm wire, due to line-to-line potentials, is zero. But if a surge passes along the three hases relatively to the ground, then a big frequency oscillatory current is induced in the alarm wire and easily passes throu h the condenser 6 to the coherer. The e ect of this current upon the coherer permits the battery to ring the alarm and operate the relay. The object of shunting a reactance across the coherer is to render it insensible to generator frequency but responsive to higher frequencies. The singlealarm wire shows only line-to-ground disturbances, so long as the phases are balanced, and shows the efl'ect equally well for all three phases. When the insulationof one phase becomes defective, then it is important to locate the base on which the trouble exists. This can e done by providing each line conductor with an individual alarm wire 14 15 16, as shown in Fig. 4, each connected with its own alarm circuit, which must be so de-. signed as not to respondto normal potential.

Instead of running one or more wires parallel to the line conductors, the arrangement shown in Fig. 5 may be adopted, in which each line conductor is connected to a neutral point through a capacity '17 and a resistance 18. An alarm 19 is placed in a local circuit in shunt to said resistance,-and a movable contact 20 enables more or less of said resistance to be shunted. A battery 21 and a coherer 22 are included in each alarm circuit. The neutral point is grounded through aresistance 23 which is shunted by an alarm circuit like those connected with the line conductors.

When a short circuit occurs between two. line conductors, or between one line conductor and ground, a surge of high frequency occurs which is shunted through the alarm circuit and breaks down the coherer resistance and permits the battery to sound the alarm.

What I claim as new and desire to secure by Letters Patent of the United States, is,

1. In a surge alarm for an electric conductor, the combination'of a coherer, means connected in shunt to said coherer to render it insensible to oscillations of the normal frequency of the current in said conductor but responsive to oscillations of abnormally high frequency, means for impressing upon said coherer oscillations of a frequency dependent upon the oscillations on said conductor, and an indicating device responsive to current flow on said coherer.

2. In a surge alarm for an electric conductor, the combination of a coherer, an indicating device responsive to flow of current through said coherer, and a wire in inductive relation to said conductor and in operative relation to said coherer for impressing upon said coherer the potential induced in said wire by potential variations on said conductor.

3. In a surge alarm for transmission lines, the combination of a coherer, indicating means responsive. to flow of current through said coherer, a condenser connected in series with said coherer, and an alarm wire mounted inlnductive'relatlon to said transmission line and connected to said condenser.

to impress upon said condenser and said coherer the potential induced in said alarm wire by variations of potential on said transmission line.

4. In a surge alarm for an electric conductor, the combination with a coherer 1'8";

means for subjecting said coherer to oscilla tions dependent upon the oscillations on said conductor, an indicating device responsive to flow of current through said coherer, and an inductance in shunt to said coherer proportioned to render said coherer insensible to oscillations of the normal frequency derived from the conductor but res onsive to oscillations of abnormally high requency.

6. A storm and surge alarm for high tension transmission lines, comprisin a wire parallel with a line and grounde at one end, a condenser and a coherer in series with said .Wire, and an alarm circuit in shunt to said coherer.

7. A storm and surge alarm for a high tension transmission line, com rising a w1re arranged equidistant from the conductors of said line and grounded at one end, a condenser and a coherer in series with said wire an inductance in shunt to said coherer, an an alarm circuit controlled by said coherer.

In witness whereof, I have hereunto set my'hand this 31st day of August, 1908.

ELMER E. F. CREIGI-ITON. .Witnesses:

BENJAMIN B. HULL, MARGARET E. WOOLLEY. 

